Film and packaging body

ABSTRACT

An object of the present invention is to provide a film that is resistant to the effects of the surface condition of an adherend such as a carrier tape and demonstrates only small fluctuations in peel strength. The film according to the present invention is provided with a surface layer. The surface layer is formed by using a polymer blend as the main component thereof. The polymer blend comprises at least two types of single segment polymers, at least two types of multi-segment polymers, or at least one type of single segment polymer and at least one type of multi-segment polymer. In the film according to the present invention, the maximum value of the absolute value of the difference in solubility parameter values among all segments in the polymer blend is 0.40 to 1.40.

TECHNICAL FIELD

The present invention relates to a film that can be used for, forexample, food packaging or electronic component packaging. In addition,the present invention relates to a packaging body provided with thatfilm.

The present application claims priority on the basis of Japanese PatentApplication No. 2011-074178, filed in Japan on Mar. 30, 2011, thecontents of which are incorporated herein by reference.

BACKGROUND ART

A cover tape that undergoes interfacial peeling when peeled from acarrier tape has been previously proposed (see, for example, PatentDocument 1).

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: Japanese Unexamined Patent Application, First    Publication No. 2010-173673

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, in the case of the cover tape as described above, there areconsiderable fluctuations in peel strength as a result of being easilyaffected by the surface condition of the carrier tape. Thus, when thisinterfacial peeling-type cover tape is peeled from the carrier tape, thecarrier tape frequently vibrates. When the carrier tape vibrates in thismanner, there is the problem of an electronic component jumping out ofthe carrier tape.

An object of the present invention is to provide a film that isresistant to the effects of the surface condition of an adherend such asa carrier tape and demonstrates only small fluctuations in peelstrength.

Means for Solving the Problems

(1) The film according to the present invention is provided with asurface layer (adhesive layer). Furthermore, the film may be formed onlyfrom a surface layer (namely, a single-layer film), or may be formedfrom the surface layer and another layer (namely, a multi-layer film).The surface layer is formed having a polymer blend as a main componentthereof. The polymer blend comprises at least two types of singlesegment polymers, at least two types of multi-segment polymers, or atleast one type of single segment polymer and at least one type ofmulti-segment polymer. Furthermore, in the present application, a“single segment polymer” refers to a polymer that has only one segment,and is a homopolymer, randomly copolymerized polymer or alternatelycopolymerized polymer. In addition, in the present application, a“multi-segment polymer” refers to a polymer having two or more segments,and is either a block copolymerized polymer or graft copolymerizedpolymer. In addition, in the present application, a segment refers to aportion having 10 or more repeating constituent units. In the filmaccording to the present invention, the maximum value of the absolutevalue of the difference in solubility parameter values among allsegments in the polymer blend is 0.40 to 1.40. Furthermore, in thepresent application, solubility parameter refers to the Hildebrandsolubility parameter. In addition, the maximum value of the absolutevalue of the difference in solubility parameter values is preferably0.90 to 1.30 and more preferably 1.00 to 1.20.

When a film satisfying the aforementioned condition is adhered to anadhered by thermal adhesion or an adhesive through the surface layer,the film can be peeled off while causing cohesive failure of the surfacelayer when peeling the film from the adherend. In general, peeling withcohesive failure is less susceptible to the effects of the surfacecondition of the adherend and there is less fluctuation in peel strengthin comparison with interfacial peeling. Consequently, this film isresistant to the effects of the surface condition of the adherend, andin cases it is peeled from an adherend after being adhered thereto,fluctuations in peel strength can be reduced.

(2) In the film according to (1) above, two segments having solubilityparameter values serving as the basis for calculating the maximum value(to be referred to as “specific segments”) are preferably contained at15 parts by weight to 60 parts by weight based on 100 parts by weight ofthe polymer blend. In addition, the weight ratio of one specific segmentto the other specific segment is preferably within the range of 30:70 to70:30.

When a film that satisfies the aforementioned conditions is adhered toan adherend by thermal adhesion or adhesive through the surface layer,the film can be peeled off while causing cohesive failure of the surfacelayer when the film is peeled from the adherend. In general, peelingwith cohesive failure is less susceptible to the effects of the surfacecondition of the adherend and there is less fluctuation in peel strengthin comparison with interfacial peeling. Consequently, this film isresistant to the effects of the surface condition of the adherend, andin cases it is peeled from the adherend after being adhered thereto,fluctuations in peel strength can be reduced.

(3) In the film according to (1) or (2) above, at least one type ofsegment has thermal adhesiveness. In addition, the surface layerfunctions as a thermal adhesive layer.

Consequently, this film can be adhered to an adherend by thermaladhesion.

(4) The packaging body according to the present invention is providedwith the film according to (3) above and a packaging container. Theopening of the packaging container is covered with the aforementionedfilm. The absolute value of the difference between the solubilityparameter value of the segment having thermal adhesiveness and thesolubility parameter value of the main component of the resincomposition that forms the surface around the opening of the packagingcontainer is 1.90 or less. Furthermore, the main component referred tohere refers to that which accounts for 50% by weight or more of theresin composition.

In a packaging body that satisfies the aforementioned condition, thefilm is favorably adhered to the packaging container prior to opening,and fluctuations in peel strength of the film during opening can bereduced.

(5) In the packaging body according to (4) above, the peel strength ofthe film with respect to the packaging container is preferably 0.1 N to1.0 N. Furthermore, the aforementioned peel strength is measured incompliance with standards when using a carrier tape having a width of 8mm as described in JIS C-0806-3.

In a packaging body that satisfies the aforementioned condition, thefilm is favorably adhered to the packaging container prior to opening,and the film can be easily peeled off during opening.

Effects of the Invention

The film according to the present invention is resistant to the effectsof the surface condition of an adherend, and in cases it is peeled froman adhered after being adhered thereto, fluctuations in peel strengthcan be reduced.

In addition, as was previously described, this film is peeled off whilecausing cohesive failure of the surface layer when peeled from anadherend after having been adhered by thermal adhesion or an adhesivethrough the surface layer. Consequently, this film not only undergoesfewer changes in peel strength over time than conventional interfacialadhesion-type film, but also demonstrates less susceptibility to theeffects of the materials of the adherend on peel strength, and is alsoless likely to peel off spontaneously in cases of being transportedwhile adhered to the adherend.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a packaging body according to anembodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line A-A of the packagingbody shown in FIG. 1.

FIG. 3 is an enlarged cross-sectional view of portion P of FIG. 2.

FIG. 4 is a perspective view showing the state of a cover tape beingpeeled from a carrier tape.

FIG. 5 is an overhead view showing the state after a cover tape has beenpeeled from a carrier tape.

BEST MODE FOR CARRYING OUT THE INVENTION

As shown in FIGS. 1 and 2, a packaging body 100 according to anembodiment of the present invention mainly comprises a cover tape 200and a carrier tape (packaging container) 300. The following providesdetailed descriptions of the cover tape 200 and the carrier tape 300,respectively.

<Cover Tape>

As shown in FIG. 3, the cover tape 200 is a laminated film comprising abase material layer 210, an intermediate layer 220 and an adhesive layer(surface layer) 230.

The base material layer 210 is preferably a transparent, highly rigid,biaxially oriented film of a polyester resin such as polyethyleneterephthalate (PET) or polyethylene naphthalate (PEN), a polyolefinresin such as polyethylene or polypropylene, or a polyamide resin suchas Nylon®. The thickness of the base material layer 210 is preferably 6μm to 100 μm. In addition, the base material layer 210 may be subjectedto antistatic treatment on one side thereof. In addition, the basematerial layer 210 may also be subjected to surface treatment such ascorona treatment, plasma treatment or sandblasting treatment asnecessary on the side on which the intermediate layer 220 or theadhesive layer 230 is formed. In addition, the base material layer 210may be laminated with the previously mentioned oriented film for thepurpose of enhancing mechanical strength of the cover tape 200.

The intermediate layer 220 is formed from, for example, polyethylene,polyethylene-vinyl acetate copolymer, ethylene-acrylic copolymer orpolyurethane. Furthermore, low-density polyethylene is preferable forthe polyethylene. In addition, the thickness of the intermediate layer220 is preferably 10 μm to 50 μm. Furthermore, the intermediate layer220 may be omitted.

Examples of methods used to form the intermediate layer 220 on the basematerial layer 210, namely a base material film, include dry laminationand extrusion lamination. Furthermore, extrusion lamination ispreferable in consideration of the flexibility of the base materiallayer 210.

The adhesive layer (surface layer) 230 is formed from a polymer blend.This polymer blend may comprise a plurality of single segment polymers,may comprise a plurality of multi-segment polymers, or may comprise atleast one type of single segment polymer and at least one type ofmulti-segment polymer. Furthermore, in the present embodiment, a “singlesegment polymer” refers to a polymer having only one segment, and is ahomopolymer, randomly copolymerized polymer or alternately copolymerizedpolymer. In addition, a “multi-segment polymer” refers to a polymerhaving two or more segments and is a block copolymerized polymer orgraft copolymerized polymer. In the present embodiment, the maximumvalue of the absolute value of the difference in solubility parametervalues among all segments in the polymer blend is 0.40 to 1.40.Furthermore, an electrically conductive substance may be dispersed inthis adhesive layer. In the case the maximum value of the absolute valueof the difference in solubility parameter values among all segments inthe polymer blend is less than 0.4, interfacial peeling occurs due to anincrease in cohesive force, thereby resulting in increasedsusceptibility to the effects of the surface condition of the adherendand causing large fluctuations in peel strength, while in the case themaximum value exceeds 1.40, adequate peel strength is unable to beobtained due to a decrease in cohesive force, thereby resulting in theoccurrence of the problem of poor film formation and making thisundesirable.

Furthermore, at least one type of single segment polymer andmulti-segment polymer contained in the polymer blend is preferably athermally adhesive resin, incompatible resin insoluble in a thermallyadhesive resin or antistatic resin. In addition, all of a thermaladhesive resin, incompatible resin insoluble in a thermal adhesive resinand antistatic resin are more preferably contained in the polymer blend.Furthermore, the polymer blend has a phase-separated structure in suchcase.

Examples of thermal adhesive resins include polyolefin-based resins,polystyrene-based resins, polyester-based resins, vinyl acetate-basedresins, polyurethane resins and acrylic resins.

Examples of vinyl acetate-based resins and acrylic resins include vinylchloride-vinyl acetate copolymers, ethylene-acrylic acid copolymers,ethylene-methyl acrylate random copolymers, ethylene-methyl methacrylaterandom copolymers, ethylene-ethyl acrylate random copolymers,ethylene-ethyl methacrylate random copolymers, ethylene-butyl acrylaterandom copolymers and ethylene-vinyl acetate copolymers.

Examples of polyolefin-based resins include polyethylene, polypropyleneand ethylene-α olefin copolymers.

Examples of polystyrene-based resins include polystyrene,styrene-butadiene-styrene block copolymers (SBS),styrene-ethylene-butylene-styrene block copolymers (SEBS),styrene-isoprene-styrene block copolymers (SIS),styrene-ethylene-propylene-styrene block copolymers (SEPS) andhydrogenated styrene-butadiene random copolymers (HSBR).

Examples of polyester-based resins include polyethylene terephthalate,polybutylene terephthalate and polyethylene naphthalate.

In the case the thermal adhesive resin is an ethylene-methyl acrylaterandom copolymer or ethylene-methyl methacrylate random copolymer,examples of incompatible resins include methyl methacrylate-styrenerandom copolymers and polystyrene resin.

Among the aforementioned thermal adhesive resins, acrylic resins,polyolefin-based resins and vinyl acetate-based resins are preferable,and among these, ethylene-acrylic acid copolymers, ethylene-methylmethacrylate random copolymers and ethylene-vinyl acetate copolymers areparticularly preferable.

Examples of antistatic resins include nonionic polyethers such aspolyethylene oxide, crosslinked polyethylene oxides, polyethylene oxidecopolymers, polyethylene glycol, polyethylene glycol copolymers (such aspolypropylene-polyethylene glycol block copolymers) or polyethyleneglycol-polyolefin copolymers; quaternary ammonium-based resins such asquaternary ammonium base-containing methacrylate copolymers, quaternaryammonium base-containing maleimide copolymers or quaternary ammoniumbase-containing methacrylic copolymers; sulfonic acid-based resins suchas sodium polystyrene sulfonate; ionomers containing monovalent ionssuch as potassium; polyethers containing Li ions such as Liion-containing polyether-polyolefin copolymers; polyether esteramide-based resins; ethylene oxide-epichlorhydrin-based resins andpolyether ester-based resins.

Among the aforementioned antistatic resins, nonionic polyethers andpolyethers containing Li ions are preferable, and among these,polyethylene glycol-polyolefin copolymers and Li ion-containingpolyether-polyolefin copolymers are particularly preferable.

The two segments having solubility parameter values used as the basisfor calculating the aforementioned maximum value (to be referred to as“specific segments”) are preferably contained at 15 parts by weight to60 parts by weight, and more preferably at 20 parts by weight to 50parts by weight, based on 100 parts by weight of the polymer blend. Inthe case of being contained at less than 15 parts by weight, sealabilityand antistatic properties cannot be realized simultaneously, while inthe case of being contained at greater than 60 parts by weight,sealability or antistatic properties decrease, thereby making thisundesirable.

The weight ratio of one of the specific segments to the other specificsegment is preferably within the range of 30:70 to 70:30. In the casethe weight ratio of one of the specific segments to the other specificsegment is less than 30 or greater than 70, sealability or antistaticproperties decrease, thereby making this undesirable.

Although there are no particular limitations thereon, the thickness ofthe cover tape 200 is preferably 500 μm or less, more preferably 200 μmor less and even more preferably 100 μm or less. In addition, thethickness of the cover tape 200 is preferably 10 μm or more, morepreferably 20 μm or more and even more preferably 30 μm or more.

Examples of methods used to form the adhesive layer 230 on the basematerial film or intermediate layer, 220 include dry lamination andextrusion lamination. Furthermore, extrusion lamination is preferable inconsideration of the flexibility of the base material layer 210.

<Carrier Tape (Packaging Container)>

As shown in FIGS. 1 and 2, the carrier tape 300 has pockets 310 andsprocket holes 320 formed therein.

There are no particular limitations on the material of the carrier tape300, and examples thereof include various types of resins such aspolystyrene-based resins, polyethylene-based resins, polypropylene-basedresins, polyester-based resins (such as polyethylene terephthalateresin), and polycarbonate-based resins.

Furthermore, in the present embodiment, although the absolute value ofthe difference between the “solubility parameter value of the maincomponent of the carrier tape 300” and the “solubility parameter valueof the adhesive resin of the cover tape 200” is preferably as small aspossible, it is at least 1.90 or less and preferably 1.85 or less.Furthermore, a main component as referred to here refers to thataccounting for 50% by weight or more of the material that composes thecarrier tape 300.

An electrically conductive filler such as carbon black, graphite orcarbon fiber is preferably dispersed in the material of the carrier tape300. This electrically conductive filler imparts electrical conductivityto the carrier tape 300 and inhibits the carrier tape 300 from becomingelectrically charged. Consequently, an electronic component 400 packagedwith the packaging body 100 is not damaged easily by static electricityof the carrier tape 300.

As shown in FIG. 1, a plurality of the pockets 310 is formed at equalintervals along the lengthwise direction of the carrier tape 300 atthose portions that house the electronic component 400. These pockets310 are formed by, for example, hot press molding, hot vacuum molding orhot pressure molding of a material sheet of the carrier tape 300.

As shown in FIG. 1, the sprocket holes 320 are a plurality of holesformed at equal intervals along the lengthwise direction of the carriertape 300. These sprocket holes 320 are formed at locations that are notcovered by the cover tape 200 when the cover tape 200 is adhered to thecarrier tape 300. The sprocket holes 320 engage with teeth of a sprocketwheel (not shown). The carrier tape 300 is transported when the sprocketwheel rotates while the sprocket wheel is engaged with the sprocketholes 320.

<Adhesion of Cover Tape and Carrier Tape>

The cover tape 200 is heat-sealed to the carrier tape 300. This heatsealing is carried out using, for example, a sealer. Heat sealing isnormally carried out over a standard width of 0.3 mm to 1.0 mm along thelengthwise direction of the cover tape 200 so as to pass over both edgesof the pockets 310 in the direction of width.

<Peeling of Cover Tape>

As shown in FIGS. 4 and 5, when the cover tape 200 according to thepresent embodiment is peeled from the carrier tape 300, the adhesivelayer 230 undergoes cohesive failure. As a result, a state results inwhich a portion of the adhesive layer 230 on the cover tape side ispeeled off (see reference symbol RC in FIG. 4), while the remainder RSof the adhesive layer 230 on the carrier tape side remains on thecarrier tape 300.

The peel strength of the film (in compliance with the standards whenusing a carrier tape having a width of 8 mm as described in JISC-0806-3) with respect to the carrier tape (packaging container) ispreferably 0.1 N to 1.0 N and more preferably 0.2 N to 0.7 N.

In the case the peel strength is less than 0.1N, spontaneous peelingoccurs easily, while in the case the peel strength exceeds 1.0 N, thereis increased susceptibility to the occurrence of problems such as anelectronic component jumping out of the carrier tape due to vibration ofthe carrier tape, thereby making this undesirable.

<Characteristics of Cover Tape According to Present Embodiment>

(1) The cover tape 200 according to the present embodiment undergoescohesive failure when peeled from the carrier tape 300. Consequently,this film is resistant to the effects of the surface condition of anadherend, and in cases in which it is peeled from an adherend afterbeing adhered thereto, fluctuations in peel strength can be reduced.

(2) In the present embodiment, the absolute value of the differencebetween the “solubility parameter value of the main component of thecarrier tape 300” and the “solubility parameter value of the adhesiveresin of the cover tape 200” is 1.90 or less. In general, two materialsare more favorably adhered the closer their solubility parameter values.Thus, the carrier tape 300 and the cover tape 200 according to thepresent embodiment are favorably adhered.

<Variations>

(A) Although the cover tape 200 according to the previous embodiment washeat-sealed to the carrier tape 300 through the adhesive layer 230, thecover tape 200 may also be adhered to the carrier tape 300 through anadhesive. Furthermore, in such case, a thermal adhesive resin may not becontained in the adhesive layer. However, even in such a case, theadhesive layer is required to undergo cohesive failure.

(B) Although the intermediate layer 220 was provided in the cover tape200 according to the previous embodiment, the intermediate layer 220 mayalso be omitted as was previously described.

(C) Although not specifically mentioned in the previous embodiment, anantistatic layer may also be separately provided in the cover tape 200.Furthermore, the antistatic layer is preferably provided between thebase material layer 210 and the intermediate layer 220 (in the case of athree-layer configuration) or between the base material layer 210 andthe adhesive layer 230 (in the case of a two-layer configuration).Furthermore, examples of the antistatic layer include urethaneisocyanate in which alkyl quaternary ammonium ethosulfate and propylenecarbonate are dispersed.

(D) Although the adhesive resin in the adhesive layer 230 of the covertape 200 according to the previous embodiment was a single segmentpolymer, the adhesive resin may also be a multi-segment polymer, or inother words, a block copolymer or graft copolymer. In such case, theabsolute value of the difference between the “solubility parameter valueof the segment that imparts adhesion” and the “solubility parametervalue of the main component of the carrier tape 300” is preferably 1.90or less.

The following provides more detailed explanations of the cover tape andpackaging body according to the present invention by indicating examplesand comparative examples. Furthermore, these examples and comparativeexamples do not limit the present invention.

Example 1

1. Preparation of Polymer Blend

An ethylene-methyl acrylate random copolymer (to be referred to as an“EMA segment”) (trade name: Elvaloy AC 1820, Du Pont-MitsuiPolychemicals Co., Ltd.) was prepared for use as an adhesive resin, amethyl methacrylate-styrene random copolymer (to be referred to as an“MS segment”) (trade name: Atorete MM70, Nippon A & L, Inc.) wasprepared for use as an incompatible resin, and apolypropylene-polyethylene glycol block copolymer (to be referred to asa “PP-PEG resin”) (trade name: Pelestat 212, Sanyo Chemical Industries,Ltd.) was prepared for use as an antistatic resin.

Furthermore, the PP-PEG resin comprises a polypropylene segment (to bereferred to as a “PP segment”) and a polyethylene glycol segment (to bereferred to as a “PEG segment”). The copolymerization ratio of thePP-PEG resin (weight ratio) was such that the ratio of the PP segment tothe PEG segment was 50:50.

60 parts by weight of the EMA segment, 10 parts by weight of the MSsegment and 30 parts by weight of the PP-PEG segment were mixed, and themixture thereof was melted and blended using a twin-screw extruder underconditions of a cylinder temperature of 180° C. to prepare pellets.Furthermore, in the case of considering the mixing ratio in segmentunits, the mixed weight ratio of the EMA segment, MS segment, PP segmentand PEG segment was 60:10:15:15.

(1) Details of Each Segment

The following describes details of each segment.

a) EMA Segment

Copolymerization ratio (weight ratio): ethylene:methyl acrylate=80:20

Solubility parameter value: 8.34-8.51 b) MS Segment

Copolymerization ratio (weight ratio): Methyl methacrylate:styrene=70:30

Solubility parameter value: 8.95-9.38

c) PP Segment

Solubility parameter value: 8.10

d) PEG Segment

Solubility parameter value: 8.63

(2) Absolute Values of Difference in Solubility Parameter

Values between each Segment The absolute values of the difference insolubility parameter values among all segments in the aforementionedpolymer blend were as indicated below.

EMA segment—MS segment: 0.44 (min.), 1.04 (max.)

EMA segment—PP segment: 0.24 (min.), 0.41 (max.)

EMA segment—PEG segment: 0.12 (min.), 0.29 (max.)

MS segment—PP segment: 0.85 (min.), 1.28 (max.)

MS segment—PEG segment: 0.32 (min.), 0.75 (max.)

PP segment—PEG segment: 0.53 (min.)

(3) Maximum Value of Absolute Values of Difference in SolubilityParameter Values Among Segments

The maximum value of the absolute values of the difference in solubilityparameter values among the segments was within the range of 0.40 to 1.40based on a minimum value of 0.85 and a maximum value of 1.28 asindicated above. Furthermore, those segments having solubility parametervalues used as the basis for calculating the maximum value were the MSsegment and PP segment. The MS segment and PP segment are contained inthe polymer blend at 25 parts by weight based on 100 parts by weight ofthe polymer blend.

2. Production of Cover Tape

A hot melt of the aforementioned pellets was extruded onto apolyethylene terephthalate biaxially oriented film (Toyo Boseki Co.,Ltd.) by extrusion lamination to produce a cover tape having a two-layerstructure.

3. Peel Test

(1) Carrier Tape

A carrier tape (A) comprising a mixture of 80 parts by weight ofimpact-resistant polystyrene (trade name: HT516, A & M Styrene Co.,Ltd.), 5 parts by weight of ethylene-vinyl alcohol copolymer (tradename: Evaflex P2505, Du Pont-Mitsui Polychemicals Co., Ltd.) and 15parts by weight of carbon black (trade name: Denka Black Particles,Denki Kagaku Kogyo Kabushiki Kaisha) (to be referred to as “PS carriertape”), and a carrier tape (B) comprising a mixture of 67 parts byweight of polycarbonate, 22 parts by weight of PCTG (trade name:SKYGREEN J2003, SK Chemicals Co., Ltd.) and 11 parts by weight of carbonblack (trade name: Ketjen Black EC, Ketjen Black International Co.) (tobe referred to as “PC carrier tape”) were prepared for use as carriertape.

Furthermore, the main component of the PS carrier tape isimpact-resistant polystyrene, and the solubility parameter value thereofis 8.60 to 9.10. In addition, the main component of the PC carrier tapeis polycarbonate, and the solubility parameter value thereof is 9.80 to10.00.

Thus, the absolute values of the difference between the “solubilityparameter value of the main component of PS carrier tape” and the“solubility parameter value of the EMA segment serving as the adhesiveresin of the cover tape” were all 1.90 or less based on a minimum valueof 0.09 and a maximum value of 0.76.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.29 and maximum value of 1.66.

(2) Adhesion of Cover Tape to Carrier Tape

The aforementioned cover tape was heat-sealed to the PS carrier tape andPC carrier tape, respectively. Furthermore, heat sealing was carried outusing a sealer (trade name: MBM-4000, Ismeca) under conditions of asealing temperature of 180° C., sealing time of 0.3 seconds and sealingpressure of 9.8 N.

(3) Peel Test

Peel strength was taken to be the average load value when the cover tapewas peeled from the PC carrier tape at a peeling angle of 165° to 180°in compliance with standards when using a carrier tape having a width of8 mm as described in JIS C-0806-3. Furthermore, the peel strength of thecover tape with respect to the PC carrier tape according to the presentexample was 0.55 N (see Table 1)

In addition, the adhesive layer underwent cohesive failure when thecover tape according to the present example was peeled from the PCcarrier tape and PS carrier tape (see Table 1)

Example 2

A cover tape was prepared and a peel test was carried out in the samemanner as Example 1 with the exception of using 65 parts by weight ofthe EMA segment, 5 parts by weight of the MS segment and 30 parts byweight of the PP-PEG resin. Furthermore, the MS segment and PP segmentwere contained at 20 parts by weight in the polymer blend based on 100parts by weight of the polymer blend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.53 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1)

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.09 and maximum value of 0.76.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.29 and maximum value of 1.66.

Example 3

A cover tape was prepared and a peel test was carried out in the samemanner as Example 1 with the exception of using a methylmethacrylate-styrene random copolymer (to be referred to as an “MSsegment”) (trade name: Estyrene MS600NT, Nippon Steel Chemical Co.,Ltd.) instead of the methyl methacrylate-styrene random copolymer usedin Example 1 (trade name: Atorete MM70, Nippon A & L, Inc.).Furthermore, the copolymerization ratio and solubility parameter valueof the MS segment according to the present example were as indicatedbelow.

(1) Details of MS Segment

Copolymerization ratio (weight ratio): Methyl methacrylate:styrene=60:40

Solubility parameter value: 8.90-9.34

(2) Absolute Values of Difference in Solubility Parameter Values betweeneach Segment

The absolute values of the difference in solubility parameter valuesamong all segments in the aforementioned polymer blend were as indicatedbelow.

EMA segment—MS segment: 0.39 (min.), 1.00 (max.)

EMA segment—PP segment: 0.24 (min.), 0.41 (max.)

EMA segment—PEG segment: 0.12 (min.), 0.29 (max.)

MS segment—PP segment: 0.80 (min.), 1.24 (max.)

MS segment—PEG segment: 0.27 (min.), 0.71 (max.)

PP segment—PEG segment: 0.53 (min.)

(3) Maximum Value of Absolute Values of Difference in SolubilityParameter Values among Segments

The maximum value of the absolute values of the difference in solubilityparameter values among the segments was within the range of 0.40 to 1.40based on a minimum value of 0.80 and a maximum value of 1.24 asindicated above. Furthermore, those segments having solubility parametervalues used as the basis for calculating the maximum value were the MSsegment and PP segment. The MS segment and PP segment are contained inthe polymer blend at 25 parts by weight based on 100 parts by weight ofthe polymer blend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.28 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1)

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.09 and maximum value of 0.76.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.29 and maximum value of 1.66.

Example 4

A cover tape was prepared and a peel test was carried out in the samemanner as Example 1 with the exception of using a methylmethacrylate-styrene random copolymer (to be referred to as an “MSsegment”) (trade name: Estyrene MS300, Nippon Steel Chemical Co., Ltd.)instead of the methyl methacrylate-styrene random copolymer used inExample 1 (trade name: Atorete MM70, Nippon A & L, Inc.). Furthermore,the copolymerization ratio and solubility parameter value of the MSsegment according to the present example were as indicated below.

(1) Details of MS Segment

Copolymerization ratio (weight ratio): Methyl methacrylate:styrene=30:70

Solubility parameter value: 8.75-9.22

(2) Absolute Values of Difference in Solubility Parameter Values betweeneach Segment

The absolute values of the difference in solubility parameter valuesamong all segments in the aforementioned polymer blend were as indicatedbelow.

EMA segment—MS segment: 0.24 (min.), 0.88 (max.)

EMA segment—PP segment: 0.24 (min.), 0.41 (max.)

EMA segment—PEG segment: 0.12 (min.), 0.29 (max.)

MS segment—PP segment: 0.65 (min.), 1.12 (max.)

MS segment—PEG segment: 0.12 (min.), 0.59 (max.)

PP segment—PEG segment: 0.53 (min.)

(3) Maximum Value of Absolute Values of Difference in SolubilityParameter Values among Segments

The maximum value of the absolute values of the difference in solubilityparameter values among the segments was within the range of 0.40 to 1.40based on a minimum value of 0.65 and a maximum value of 1.12 asindicated above. Furthermore, those segments having the solubilityparameter values used as the basis for calculating the maximum valuewere the MS segment and PP segment. The MS segment and PP segment arecontained in the polymer blend at 25 parts by weight based on 100 partsby weight of the polymer blend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.59 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1).

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.09 and maximum value of 0.76.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.29 and maximum value of 1.66.

Example 5

A cover tape was prepared in the same manner as Example 4 with theexception of using 45 parts by weight of the EMA segment, 25 parts byweight of the MS segment and 30 parts by weight of the PP-PEG resin, anda peel test was carried out in the same manner as Example 1.Furthermore, the MS segment and PP segment were contained at 40 parts byweight in the polymer blend based on 100 parts by weight of the polymerblend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.28 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1)

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.09 and maximum value of 0.76.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.29 and maximum value of 1.66.

Example 6

A cover tape was prepared in the same manner as Example 4 with theexception of using 35 parts by weight of the EMA segment, 35 parts byweight of the MS segment and 30 parts by weight of the PP-PEG resin, anda peel test was carried out in the same manner as Example 1.Furthermore, the MS segment and PP segment were contained at 50 parts byweight in the polymer blend based on 100 parts by weight of the polymerblend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.14 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1).

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.09 and maximum value of 0.76.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.29 and maximum value of 1.66.

Example 7

A cover tape was prepared and a peel test was carried out in the samemanner as Example 1 with the exception of using a methylmethacrylate-styrene random copolymer (to be referred to as an “MSsegment”) (trade name: Estyrene MS200NT, Nippon Steel Chemical Co.,Ltd.) instead of the methyl methacrylate-styrene random copolymer usedin Example 1 (trade name: Atorete MM70, Nippon A & L, Inc.).Furthermore, the copolymerization ratio and solubility parameter valueof the MS segment according to the present example were as indicatedbelow.

(1) Details of MS Segment

Copolymerization ratio (weight ratio): Methyl methacrylate:styrene=20:80

Solubility parameter value: 8.70-9.18

(2) Absolute Values of Difference in Solubility Parameter Values betweeneach Segment

The absolute values of the difference in solubility parameter valuesamong all segments in the aforementioned polymer blend were as indicatedbelow.

EMA segment—MS segment: 0.19 (min.), 0.84 (max.)

EMA segment—PP segment: 0.24 (min.), 0.41 (max.)

EMA segment—PEG segment: 0.12 (min.), 0.29 (max.)

MS segment—PP segment: 0.60 (min.), 1.08 (max.)

MS segment—PEG segment: 0.07 (min.), 0.55 (max.)

PP segment—PEG segment: 0.53 (min.)

(3) Maximum Value of Absolute Values of Difference in SolubilityParameter Values among Segments

The maximum value of the absolute values of the difference in solubilityparameter values among the segments was within the range of 0.40 to 1.40based on a minimum value of 0.60 and a maximumvalue of 1.08 as indicatedabove. Furthermore, those segments having solubility parameter valuesused as the basis for calculating the maximum value were the MS segmentand PP segment. The MS segment and PP segment are contained in thepolymer blend at 25 parts by weight based on 100 parts by weight of thepolymer blend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.52 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1)

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.09 and maximum value of 0.76.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.29 and maximum value of 1.66.

Example 8

A cover tape was prepared in the same manner as Example 7 with theexception of using 35 parts by weight of the EMA segment, 35 parts byweight of the MS segment and 30 parts by weight of the PP-PEG resin, anda peel test was carried out in the same manner as Example 1.Furthermore, the MS segment and PP segment were contained at 50 parts byweight in the polymer blend based on 100 parts by weight of the polymerblend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.34 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1).

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.09 and maximum value of 0.76.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.29 and maximum value of 1.66.

Example 9

A cover tape was prepared and a peel test was carried out in the samemanner as Example 1 with the exception of using polystyrene (to bereferred to as an “PS segment”) (trade name: Toyo Styrol G210C, ToyoStyrene Co., Ltd.) instead of the methyl methacrylate-styrene randomcopolymer used in Example 1 (trade name: Atorete MM70, Nippon A & L,Inc.). Furthermore, the solubility parameter value of the PS segmentaccording to the present example was as indicated below.

(1) Details of PS Segment

Solubility parameter value: 8.60-9.10

(2) Absolute Values of Difference in Solubility Parameter Values BetweenEach Segment

The absolute values of the difference in solubility parameter valuesamong all segments in the aforementioned polymer blend were as indicatedbelow.

EMA segment—PS segment: 0.09 (min.), 0.76 (max.)

EMA segment—PP segment: 0.24 (min.), 0.41 (max.)

EMA segment—PEG segment: 0.12 (min.), 0.29 (max.)

PS segment—PP segment: 0.50 (min.), 1.00 (max.)

PS segment—PEG segment: 0.03 (min.), 0.47 (max.)

PP segment—PEG segment: 0.53 (min.)

(3) Maximum Value of Absolute Values of Difference in SolubilityParameter Values among Segments

The maximum value of the absolute values of the difference in solubilityparameter values among the segments was within the range of 0.40 to 1.40based on a minimum value of 0.50 and a maximum value of 1.00 asindicated above. Furthermore, those segments having solubility parametervalues used as the basis for calculating the maximum value were the PSsegment and PP segment. The PS segment and PP segment are contained inthe polymer blend at 25 parts by weight based on 100 parts by weight ofthe polymer blend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.57 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1)

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.09 and maximum value of 0.76.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.29 and maximum value of 1.66.

Example 10

A cover tape was prepared and a peel test was carried out in the samemanner as Example 1 with the exception of using an ethylene-methylacrylate random copolymer (to be referred to as an “EMA segment”) (tradename: Elvaloy AC 1913, Du Pont-Mitsui Polychemicals Co., Ltd.) insteadof the ethylene-methyl acrylate random copolymer (trade name: Elvaloy AC1820, Du Pont-Mitsui Polychemicals Co., Ltd.) used in Example 1.Furthermore, the copolymerization ratio and solubility parameter valueof the EMA segment according to the present example were as indicatedbelow.

(1) Details of EMA Segment

Copolymerization ratio (weight ratio):

Ethylene:methyl acrylate=87:13

Solubility parameter value: 8.19-8.37

(2) Absolute Values of Difference in Solubility Parameter Values BetweenEach Segment

The absolute values of the difference in solubility parameter valuesamong all segments in the aforementioned polymer blend were as indicatedbelow.

EMA segment—MS segment: 0.58 (min.), 1.19 (max.)

EMA segment—PP segment: 0.09 (min.), 0.27 (max.)

EMA segment—PEG segment: 0.26 (min.), 0.44 (max.)

MS segment—PP segment: 0.85 (min.), 1.28 (max.)

MS segment—PEG segment: 0.32 (min.), 0.75 (max.)

PP segment—PEG segment: 0.53 (min.)

(3) Maximum Value of Absolute Values of Difference in SolubilityParameter Values Among Segments

The maximum value of the absolute values of the difference in solubilityparameter values among the segments was within the range of 0.40 to 1.40based on a minimum value of 0.85 and a maximum value of 1.28 asindicated above. Furthermore, those segments having solubility parametervalues used as the basis for calculating the maximum value were the MSsegment and PP segment. The MS segment and PP segment are contained inthe polymer blend at 25 parts by weight based on 100 parts by weight ofthe polymer blend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.26 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1)

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.23 and maximum value of 0.91.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.43 and maximum value of 1.81.

Example 11

A cover tape was prepared and a peel test was carried out in the samemanner as Example 1 with the exception of using an ethylene-methylmethacrylate random copolymer (to be referred to as an “EMMA segment”)(trade name: Acryft WH303F, Sumitomo Chemical Co., Ltd.) instead of theethylene-methyl acrylate random copolymer (trade name: Elvaloy AC 1820,Du Pont-Mitsui Polychemicals Co., Ltd.) used in Example 1. Furthermore,the copolymerization ratio and solubility parameter value of the EMMAsegment according to the present example were as indicated below.

(1) Details of EMMA Segment

Copolymerization ratio (weight ratio): Ethylene:methylmethacrylate=82:18

Solubility parameter value: 8.12-8.35

(2) Absolute Values of Difference in Solubility Parameter Values BetweenEach Segment

The absolute values of the difference in solubility parameter valuesamong all segments in the aforementioned polymer blend were as indicatedbelow.

EMMA segment—MS segment: 0.60 (min.), 1.26 (max.)

EMMA segment—PP segment: 0.02 (min.), 0.25 (max.)

EMMA segment—PEG segment: 0.28 (min.), 0.51 (max.)

MS segment—PP segment: 0.85 (min.), 1.28 (max.)

MS segment—PEG segment: 0.32 (min.), 0.75 (max.)

PP segment—PEG segment: 0.53 (min.)

(3) Maximum Value of Absolute Values of Difference in SolubilityParameter Values among Segments

The maximum value of the absolute values of the difference in solubilityparameter values among the segments was within the range of 0.40 to 1.40based on a minimum value of 0.85 and a maximum value of 1.28 asindicated above. Furthermore, those segments having solubility parametervalues used as the basis for calculating the maximum value were the MSsegment and PP segment. The MS segment and PP segment are contained inthe polymer blend at 25 parts by weight based on 100 parts by weight ofthe polymer blend.

(4) Results of Peel Test

The peel strength of the cover tape with respect to the PC carrier tapeaccording to the present example was 0.21 N. In addition, the adhesivelayer of the cover tape according to the present example underwentcohesive failure when peeled from the PC carrier tape and PS carriertape (see Table 1)

Furthermore, the absolute values of the difference between the“solubility parameter value of the main component of the PS carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 0.25 and maximum value of 0.98.

In addition, the absolute values of the difference between the“solubility parameter value of the main component of the PC carriertape” and the “solubility parameter value of the EMA segment serving asthe adhesive resin of the cover tape” were all 1.90 or less based on aminimum value of 1.45 and maximum value of 1.88.

TABLE 1 Adhesive Resin Incompatible Resin Antistatic Resin Peel BlendingBlending Blending Max. Peeling strength SG SP value ratio SG SP valueratio SG SP value ratio diff. mode (N) Ex. 1 EMA 8.34-8.51 60 MS8.95-9.38 10 PP 8.10 15 Max.1.28 Cohesive 0.55 PEG 8.63 15 Min.0.85failure Ex. 2 EMA 8.34-8.51 65 MS 8.95-9.38 5 PP 8.10 15 Max.1.28Cohesive 0.53 PEG 8.63 15 Min.0.85 failure Ex. 3 EMA 8.34-8.51 60 MS8.90-9.34 10 PP 8.10 15 Max.1.24 Cohesive 0.28 PEG 8.63 15 Min.0.80failure Ex. 4 EMA 8.34-8.51 60 MS 8.75-9.22 10 PP 8.10 15 Max.1.12Cohesive 0.59 PEG 8.63 15 Min.0.65 failure Ex. 5 EMA 8.34-8.51 45 MS8.75-9.22 25 PP 8.10 15 Max.1.12 Cohesive 0.28 PEG 8.63 15 Min.0.65failure Ex. 6 EMA 8.34-8.51 35 MS 8.75-9.22 35 PP 8.10 15 Max.1.12Cohesive 0.14 PEG 8.63 15 Min.0.65 failure Ex. 7 EMA 8.34-8.51 60 MS8.70-9.18 10 PP 8.10 15 Max.1.08 Cohesive 0.52 PEG 8.63 15 Min.0.60failure Ex. 8 EMA 8.34-8.51 35 MS 8.70-9.18 35 PP 8.10 15 Max.1.08Cohesive 0.34 PEG 8.63 15 Min.0.60 failure Ex. 9 EMA 8.34-8.51 60 PS8.60-9.10 10 PP 8.10 15 Max.1.00 Cohesive 0.57 PEG 8.63 15 Min.0.50failure Ex. 10 EMA 8.19-8.37 60 MS 8.98-9.40 10 PP 8.10 15 Max.1.28Cohesive 0.26 PEG 8.63 15 Min.0.85 failure Ex. 11 EMMA 8.12-8.35 60 MS8.95-9.38 10 PP 8.10 15 Max.1.28 Cohesive 0.21 PEG 8.63 15 Min.0.85failure

Comparative Example 1

1. Production of Cover Tape

A hot melt of an ethylene-methyl acrylate random copolymer (trade name:Elvaloy AC 1820, Du Pont-Mitsui Polychemicals Co., Ltd.) was extrudedonto a polyethylene terephthalate biaxially oriented film (Toyo BosekiCo., Ltd.) by extrusion lamination to produce a cover tape.

2. Peel Test

A peel test was carried out in the same manner as the peel test ofExample 1.

The adhesive layer of the cover tape according to the presentcomparative example underwent interfacial peeling when peeled from acarrier tape (see Table 2)

Comparative Example 2

A cover tape was prepared and a peel test was carried out in the samemanner as Comparative Example 1 with the exception of using anethylene-methyl acrylate random copolymer (trade name: Elvaloy AC 1913,Du Pont-Mitsui Polychemicals Co., Ltd.) instead of the ethylene-methylacrylate random copolymer (trade name: Elvaloy AC 1820, Du Pont-MitsuiPolychemicals Co., Ltd.) used in Comparative Example 1.

The adhesive layer of the cover tape according to the presentcomparative example underwent interfacial peeling when peeled from acarrier tape (see Table 2).

Comparative Example 3

A cover tape was prepared and a peel test was carried out in the samemanner as Comparative Example 1 with the exception of using anethylene-methyl methacrylate random copolymer (trade name: AcryftWH303F, Sumitomo Chemical Co., Ltd.) instead of the ethylene-methylacrylate random copolymer (trade name: Elvaloy AC 1820, Du Pont-MitsuiPolychemicals Co., Ltd.) used in Comparative Example 1.

The adhesive layer of the cover tape according to the presentcomparative example underwent interfacial peeling when peeled from acarrier tape (see Table 2).

Comparative Example 4

A cover tape was prepared and a peel test was carried out in the samemanner as Comparative Example 1 with the exception of using anethylene-methyl methacrylate random copolymer (trade name: AcryftWK402,Sumitomo Chemical Co., Ltd.) instead of the ethylene-methyl acrylaterandom copolymer (trade name: Elvaloy AC 1820, Du Pont-MitsuiPolychemicals Co., Ltd.) used in Comparative Example 1.

The adhesive layer of the cover tape according to the presentcomparative example underwent interfacial peeling when peeled from acarrier tape (see Table 2)

Comparative Example 5

1. Preparation of Polymer Blend

An ethylene-methyl methacrylate random copolymer (to be referred to asan “EMMA segment”) (trade name: Acryft WK402, Sumitomo Chemical Co.,Ltd.) was prepared for use as an adhesive resin, and polypropylene (tobe referred to as a “PP segment”) (trade name: J106, Grand Polymer Co.)was prepared for use as an incompatible resin.

70 parts by weight of the EMMA segment and 30 parts by weight of the PPsegment were mixed, and the mixture thereof was melted and blended usinga twin-screw extruder under conditions of a cylinder temperature of 180°C. to prepare pellets.

(1) Details of Each Segment

The following describes details of each segment.

a) EMMA Segment

Copolymerization ratio (weight ratio): ethylene:methylmethacrylate=75:25

Solubility parameter value: 8.20-8.45

b) PP Segment

Solubility parameter value: 8.10

(2) Absolute Value of Difference in Solubility Parameter Values BetweenEach Segment

The absolute value of the difference in solubility parameter valuesbetween segments in the aforementioned polymer blend was as indicatedbelow.

EMMA segment—PP segment: 0.10 (min.), 0.35 (max.)

(3) Maximum Value of Absolute Value of Difference in SolubilityParameter Values Between Segments

The maximum value of the absolute value of the difference in solubilityparameter values between the segments was outside the range of 0.40 to1.40 based on a minimum value of 0.10 and a maximum value of 0.35 asindicated above.

2. Production of Cover Tape

A hot melt of the aforementioned pellets was extruded onto apolyethylene terephthalate biaxially oriented film (Toyo Boseki Co.,Ltd.) by extrusion lamination to produce a cover tape having a two-layerstructure.

3. Peel Test

A peel test was carried out in the same manner as the peel test ofExample 1.

The adhesive layer of the cover tape according to the presentcomparative example underwent interfacial peeling when peeled from acarrier tape (see Table 2).

TABLE 2 Adhesive Resin Incompatible Resin Blending Blending Max. SG SPvalue ratio SG SP value ratio Difference Peeling Mode Comp. Ex. 1 EMA8.34-8.51 100 — — — — Interfacial peeling Comp. Ex. 2 EMA 8.19-8.37 100— — — — Interfacial peeling Comp. Ex. 3 EMMA 8.12-8.35 100 — — — —Interfacial peeling Comp. Ex. 4 EMMA 8.20-8.45 100 — — — — Interfacialpeeling Comp. Ex. 5 EMMA 8.20-8.45 70 PP 8.10 30 Max.0.35 InterfacialMin.0.10 peeling

INDUSTRIAL APPLICABILITY

The film according to the present invention is characterized by beingresistant to the effects of the surface condition of an adherend anddemonstrating only small fluctuations in peel strength in the case ofbeing peeled from the adherend, and is useful, for example, as a covertape or a covering material for a food package.

BRIEF DESCRIPTION OF THE REFERENCE SYMBOLS

-   -   100 Packaging body    -   200 Cover tape    -   230 Adhesive layer (surface layer, thermal adhesive layer)    -   300 Carrier tape

1. A film provided with a surface layer having as a main componentthereof a polymer blend comprising at least two types of single segmentpolymers, at least two types of multi-segment polymers, or at least onetype of single segment polymer and at least one type of multi-segmentpolymer, wherein a maximum value of an absolute value of a difference insolubility parameter values among all segments in the polymer blend is0.40 to 1.40.
 2. The film according to claim 1, wherein two specificsegments having solubility parameter values serving as a basis forcalculating the maximum value are contained at 15 parts by weight to 60parts by weight based on 100 parts by weight of the polymer blend, and aweight ratio of one specific segment to the other specific segment iswithin a range of 30:70 to 70:30.
 3. The film according to claim 1,wherein at least one type of the segments has thermal adhesiveness, andthe surface layer functions as a thermal adhesive layer.
 4. A packagingbody provided with the film according to claim 3 and a packagingcontainer, an opening of which is covered by the film, wherein theabsolute value of the difference between the solubility parameter valueof the segment having thermal adhesiveness and the solubility parametervalue of the main component of a resin composition that forms a surfacearound the opening of the packaging container is 1.90 or less.
 5. Thepackaging body according to claim 4, wherein peel strength of the filmwith respect to the packaging container (as measured in compliance withstandards when using a carrier tape having a width of 8 mm as describedin JIS C-0806-3) is 0.1 N to 1.0 N.
 6. The film according to claim 2,wherein at least one type of the segments has thermal adhesiveness, andthe surface layer functions as a thermal adhesive layer.
 7. A packagingbody provided with the film according to claim 6 and a packagingcontainer, an opening of which is covered by the film, wherein theabsolute value of the difference between the solubility parameter valueof the segment having thermal adhesiveness and the solubility parametervalue of the main component of a resin composition that forms a surfacearound the opening of the packaging container is 1.90 or less.
 8. Thepackaging body according to claim 7, wherein peel strength of the filmwith respect to the packaging container (as measured in compliance withstandards when using a carrier tape having a width of 8 mm as describedin JIS C-0806-3) is 0.1 N to 1.0 N.